Depends on if the car is set up with an adapter plate to allow for use of a Chevy pattern case or do you need to use one of the aftermarket bellhousing type of units. I've used JW stuff in the past, but if I were starting from scratch, I would go with the ATI case and appropriate bellhousing. Get everything from one source to avoid fitment issues.

Chevy pattern case? Probably a Reid or if you are buying a complete trans, Hughes is close to you and they do a lot of pro tree stuff..